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Forbidden Foods: The Latest News on Food Allergies

Food Allergies: Helping Your Child Cope
Food Allergies: Helping Your Child Cope

We may all have grown up on PB&J, but times have certainly changed. "The prevalence of peanut allergy is growing and will likely continue to grow," says Parents advisor Hugh Sampson, MD, chief of pediatric allergy and immunology at Mount Sinai School of Medicine, in New York City. There's no hard data showing that reactions to foods like milk, eggs, and wheat are also rising, but many doctors believe that they are. Six to 8 percent of children under age 4 have some sort of food allergy, according to the National Institute of Allergy and Infectious Diseases, and babies and toddlers are most vulnerable. Although only about 1 percent of kids are allergic to peanuts, that number represents a 50 percent increase in the past decade. More than 200 people in the U.S. die from an allergic reaction to food each year, and most fatalities are related to peanuts. Sesame allergy, which was almost unheard of a few decades ago, is becoming increasingly common in kids, as are reports of allergic reactions to other seeds and their oils. While many kids get diagnosed after a sudden reaction, lots of children have less dramatic symptoms that parents may not realize are caused by a food allergy.

Unfortunately, even top experts aren't sure what's causing this surge -- and they're actually more confused than ever about how to help prevent food allergies. For years, doctors have told parents who have any allergies themselves to delay feeding their children eggs, peanuts, tree nuts, and fish -- but now the American Academy of Pediatrics (AAP) says that this strategy might not be beneficial after all. "It's definitely a frustrating situation for parents who want to protect their kids," says Scott Sicherer, MD, author of Understanding and Managing Your Child's Food Allergies.

It's not only food allergies that are on the rise. "In the past 20 years, we've also seen a significant increase in hay fever, asthma, and eczema," says Dr. Sampson, former president of the American Academy of Allergy, Asthma, and Immunology (AAAAI). Asthma rates in young children have tripled since the 1980s, and the percentage of Americans testing positive to one or more allergens has doubled. Doctors' best explanation is "The Hygiene Hypothesis." Some children's immune systems aren't developing properly because kids are exposed to fewer diseases and less dirt and bacteria these days, scientists theorize. Without as many germs to fight, the immune system mistakenly overreacts to foreign substances (nuts, dust, pollen) that aren't really dangerous.

If you or your partner has any kind of allergy (and more than a third of adults do), your child's risk of developing one is about 40 percent -- double the risk of children without an allergic parent. If you both have allergies, his risk rises to 60 percent. But allergies to specific foods don't run in families. "If you're allergic to shrimp, your child may be allergic to peanuts or eggs, or he may have hay fever instead," says Wesley Burks, MD, chief of pediatric allergy at Duke University Medical Center, in Durham, North Carolina. If your baby has eczema, however, you should be on the lookout for reactions to food; 40 percent of babies with the skin condition develop a food allergy.

Another factor influencing the rise of food allergies may be the way certain foods are processed. In the U.S., peanuts are typically roasted to make peanut butter, candy, and baked goods, and this process is believed to make them more allergenic. However, in countries where it's customary to boil peanuts, the prevalence of peanut allergies is much lower. The increasing popularity of foods containing sesame seeds may help explain the rise in this allergy. And according to one study, the growing rate of cesarean sections may even be fueling food allergies: Among babies whose mothers had allergies, those born by cesarean were seven times more likely to have an allergic reaction to eggs, fish, or nuts by age 2. The researchers speculate that vaginal delivery colonizes a baby's intestines with healthy bacteria that help protect against food allergies.

Certainly, the increased awareness about food allergies also makes kids more likely to get diagnosed. "Twenty years ago, there were doctors who didn't believe food allergies even existed," says Stacie Jones, MD, chief of allergy and immunology at Arkansas Children's Hospital, in Little Rock. "Now we know so much more about how to recognize and properly evaluate them."

While it's possible for any food to trigger a reaction, 80 to 90 percent of food allergies in this country are caused by eight major foods: milk, eggs, soy, wheat, peanuts, tree nuts (walnuts, cashews, almonds), fish, and shellfish (shrimp, crab, lobster). "Allergies to milk and eggs are the most common ones in babies and toddlers, followed by peanuts, soy, and wheat," says Robert Wood, MD, director of pediatric allergy and immunology at Johns Hopkins Children's Center, in Baltimore.

Doctors have been saying for years that kids usually outgrow most of these allergies by first grade, but allergies to peanuts, tree nuts, fish, and shellfish are lifelong. However, one recent study found that most kids actually remain allergic to milk and eggs until their teen years. And a 2007 Johns Hopkins study found that 79 percent of children had outgrown their peanut allergies by 16. Fish and shellfish allergies often don't develop until adolescence or adulthood, perhaps because kids usually don't eat these foods early in life. Doctors don't know yet whether kids will outgrow their allergy to sesame.

An allergic child won't have symptoms the first time he's exposed to a food, but his immune system secretly starts producing antibodies to fight the supposed invader. This can happen during breastfeeding, since a small amount of everything a mom eats is passed to her baby through her milk. In the future, when the child is exposed to that food -- either through breast milk or by eating it -- the antibodies release chemicals that trigger an allergic reaction. Symptoms can include skin flushing, itching, rashes, hives, swelling, vomiting, diarrhea, watery eyes, a runny nose, sneezing, and wheezing. Rarely, a food allergy can cause a life-threatening reaction known as anaphylaxis, in which the airways swell, blood pressure drops, and breathing shuts down.

Since there's such a range of symptoms, how can you tell if your child has a food allergy rather than a cold or a stomach bug? The best clue is the timing of her reaction: Symptoms usually appear within seconds to minutes after eating, but almost always within two hours. A skin reaction like flushing or hives is another key. "Most children with a food allergy have some kind of skin symptom soon after eating," says Dr. Sampson.

If you suspect that your child has a food allergy, ask your pediatrician for a referral to a pediatric allergist, who will perform a physical exam, take a detailed history of your child's food sensitivities, and use skin tests or blood tests to detect food-allergy antibodies. Even if your child has a mild reaction to a food, it's important to call your pediatrician. "Just because the first reaction was mild doesn't mean the next one will be too," says Dr. Wood.

It's also important to recognize the difference between an allergy and an intolerance. According to a new study, a third of parents reported that their baby or toddler had a bad reaction to a food. However, food intolerance can cause some of the same symptoms as a food allergy. While an allergy involves the immune system, an intolerance occurs when the body lacks the enzyme to digest a specific food. Symptoms can appear up to six hours after eating but are never life-threatening. Here are the key signs of both conditions.

Food Intolerance

  • Upset stomach
  • Gas and bloating
  • Abdominal cramps
  • Vomiting
  • Diarrhea

Food Allergy

  • Skin redness and itching
  • Rashes or hives
  • Red, watery eyes
  • Nasal congestion, runny nose, sneezing
  • Vomiting
  • Diarrhea
  • Swelling of the lips, face, or throat
  • Wheezing
  • Severe breathing difficulty
  • Loss of consciousness

If it turns out that your child does have a food allergy, you've got to do whatever you can to help him avoid that food. However, since he still could eat it accidentally, it's important to have medicine nearby to reverse a reaction. An over-the-counter antihistamine should relieve mild symptoms (watery eyes, runny nose, hives), but your doctor will probably give you a prescription for an EpiPen, a device that contains an easy-to-inject dose of epinephrine to reverse a severe reaction.

Thanks to a federal labeling law that went into effect in 2006, manufacturers must now say in plain language whenever packaged foods contain any of the eight most common allergens (but not sesame). In the past, parents practically needed a degree in food science in order to decipher the technical terms on the ingredient list-for example, milk was often listed as "casein" or "whey" and egg as "albumen" or "globulin." Now companies must say "milk" and "egg." This has certainly made it easier for families to shop safely.

However, the new labels can also be frustrating. As a precaution, more and more companies are now putting "advisory labeling" on products that says a product "may contain" an allergen, "is manufactured on shared equipment" with an allergen, or is "manufactured in the same facility" with an allergen. This vague language makes it tougher for parents to decide which products to avoid, and a study by the nonprofit Food Allergy and Anaphylaxis Network (FAAN) found that an increasing number of parents are actually ignoring the warnings. However, since these products could in fact be dangerous, doctors say that it's still better to be safe than sorry.

Since living with a food allergy can be tough, doctors have tried to help reduce the risk for babies who have a family history of allergies. Until recently, the AAP had recommended delaying the introduction of eggs until age 2, and peanuts, tree nuts, and fish until age 3, and had also advised that pregnant and nursing moms avoid eating peanuts.

However, even though families have been taking these precautions, the rates of food allergies have continued to rise -- and some studies have suggested that restricting these foods might actually be contributing to the problem, says Dr. Sampson. When the AAP recently reviewed all the studies that have been done, it decided that there just wasn't enough evidence to back up its previous advice. The new report suggests waiting at least four to six months before introducing solid foods but no longer advises waiting years to give children allergens like eggs, peanuts, and tree nuts. (If your child has already been diagnosed with one food allergy, however, her doctor may advise avoiding additional foods.) The new report also says there's insufficient proof that avoiding peanuts during pregnancy or breastfeeding is protective either. "However, I certainly wouldn't discourage mothers from avoiding peanuts during pregnancy or breastfeeding if they have a strong family history of food allergies," says Dr. Sampson. Here are some other steps that doctors say may in fact help reduce a child's risk.

  • Breastfeed. Nursing exclusively for at least four months is believed to strengthen a baby's immune system, and studies have found that it reduces the risk of eczema, cow's-milk allergy, and wheezing at a young age.
  • Consider formula options. If you have a family history of allergies and are not breastfeeding exclusively, using a hydrolyzed formula such as Alimentum, Nutramigen, or Good Start, which has added enzymes that change the milk proteins, may reduce the risk of eczema and food allergies. Soy formula has not been found to prevent allergies.
  • Don't start solids too soon. Wait until your baby is 4 to 6 months old before you introduce any solid foods, including cereal. After that, you don't need to avoid any foods (other than cow's milk and honey until 12 months, as well as choking hazards).
  • Make playdates. Being around other kids -- and their germs -- may help fine-tune your child's immune system and protect against all kinds of allergies, says Dr. Burks.
  • Be cautious with lotions and ointments. Avoid using ones containing milk, almond oil, or peanut oil (often listed as arachis oil) on your baby, because they may trigger an allergic reaction.

If your child does develop a food allergy, it's helpful to remember that only a tiny fraction of kids actually have life-threatening reactions. "A food allergy doesn't have to restrict a child much more than having to wear eyeglasses does," says Anne Munoz-Furlong, founder and CEO of FAAN. "Children with food allergies can do everything other children can do, except eat that food."

Within the next five years, children with a peanut allergy may be able to take a monthly shot to prevent a severe reaction, says Dr. Sampson, who is conducting research on the peanut vaccine. If it's successful, it will pave the way for similar vaccines for other food allergies. Eventually, kids may not even need to get a shot --an oral vaccine is also in the works.

Parents of nonallergic kids may find it frustrating that peanut butter and nuts are increasingly off-limits at school and other kid zones, especially when relatively few children are allergic. But others say that the potential consequences of permitting peanuts are just too serious. While it's important to teach allergic kids to take necessary precautions, such as not sharing food and asking about ingredients, it's possible that even a tiny bit of peanut dust in the air could trigger a severe reaction.

Copyright © 2008. Used with permission from the June 2008 issue of Parents magazine.

Updated May 2010

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